Black Box Testing

Abstract

Software Testing are major source of Testing which make our software efficient in working .It is even impossible some time to declare that whether the Testing phase in complete or not. The Black Box Testing is external Testing . Black Box Testing select test cases based on an analysis of the specification of a component or system without reference to its internal structure. It is like a software program, in the eyes of the tester is like a Black Box; inside which one cannot see.

Introduction

Software Testing help stakeholders to judge about the quality of their product . Software Testing allow user to generate independent view about the quality of product . Test techniques is a process or application used with the intent to find bugs in software or application .It is also used for validating and verifying software program / application or product.

Software Testing can be implemented at any time in the development process. Most of the test effort occurs after the requirements have been defined and coding has been completed. The methodology of the test is governed by the software development methodology adopted.

Objectives Of Software Testing

Basically software

Testing is the way to detect the errors from software item of program where conditions are tested to make the product more efficient and cost constructive. The main purpose of software Testing is quality assurance, reliability, validation and verification. To maintain the originality and to work the functions of software item properly, the Testing is required. A successful Testing is considered if it uncovers discovered errors. Better the software works, the more efficiently it can be used. It includes correctness and completeness of software. It ensures the quality of software item by Testing software item under some conditions.

Terms associated with Testing

Quality Assurance - All those planned or systematic actions necessary to provide confidence that a product or service is of the type and quality needed and expected by the customer.

Reliability - It is another term of consistency. If one person takes same personality test several times and always gets the same result is called reliable state.

Verification - It is the process of evaluating a system to determine whether the given product satisfied the conditions imposed at the start of that phase.

Validation - It is the process of evaluating a system during or at the end of the development process to determine whether it satisfies the conditions.

Black Box Testing. This type of Testing includes only interior working of the software. In this, the tester does not access the source code. The tester will interact with the system user interface by providing inputs and examining outputs without knowing how and where the inputs are worked upon. The representation of Black Box Testing is given in figure 2 below:

• Testing Technique
• Testing Methods
• Classification of Testing (Black Box) Technique
• Boundary Value Analysis - Errors tend to occur at the boundaries of equivalence classes rather than at the "center". It requires program to distinguish between digits and non-digits values.
• Equivalence Partitioning – It Partition the test cases into "equivalence classes". Each equivalence contains a set of "equivalent" test cases. Two test cases are considered to be equivalent. If you expect the program to process two test cases in the same way, only test one of them, thus reducing the number of test cases you have to run.

Orthogonal / Array Testing – It is a systematic, statistical way of Testing which is used when the number of inputs to the system is small, but too large allow for exhaustive Testing of every possible input to the systems. Fuzz Testing - Fuzz Testing is a Testing technique which can nonetheless reveal important bugs in your programs. It can identify real-world failure modes and signal potential avenues of attack that should be plugged before your software ships.

Graph Base Testing - Graphs are generated and cyclometric complexity considered in using the test cases in Graph base Testing. All-pairs Testing - It allows one to create a set of tests, using pairwise combinations methods, reducing several combinations of variables into a lesser set that covers most situations

State Transition Testing – State transition Testing is used in ‘finite state machine’. The system can be in a (finite) number of different states, and the transitions from one state to another are determined by the rules of the ‘machine’. This is the model on which the system and the tests are based.

Black Box Testing - Steps

I. Initially requirements and specifications of the system are examined.

II. Tester chooses valid inputs (positive test scenario) to check whether SUT processes them correctly. Also some invalid inputs (negative test scenario) are chosen to verify that the SUT is able to detect them.

III. Tester determines expected outputs for all those inputs.

IV. Software tester constructs test cases with the selected inputs.

V. The test cases are executed.

VI. Software tester compares the actual outputs with the expected outputs.

VII. Defects if any are fixed and re-tested.

Comparison of Black Box and White Box Testing Black Box Testing White Box Testing

• • Black Box Testing is a software Testing method in which the internal structure of the item being tested is not known to the tester
  • It is a higher level of Testing
  • Independent software testers are responsible for Black Box Testing
  • Programming knowledge is not required for Black Box Testing
  • Implementation knowledge is not required for Black Box Testing
  • Black Box Testing is a software Testing method in which the internal structure of the item being tested is known to the tester.
  • It is a lower level of Testing
  • Software developers are responsible for white box Testing.
  • Programming language is required for white box Testing
  • Implementation knowledge is required for white box Testing

Advantages of Black Box Testing

• • • Ease of Use - Black Box Testing do not involve in the inner functionality of the application so it’s easy to use Testing can be easily performed by the technical users.
    • Quicker test case development – Test concerns with the graphical user interface . Identification of internal paths are not needed in this . The tester will cover the GUI paths that involves in specific process.
    • Simplicity - Using Black Box Testing even complex applications can be tested that focusing on valid and invalid inputs and ensuring that the correct q24out puts are received.
    • Nicer Look To Black Box Testing

Black-box Testing seems to be stand out is that it focused on the end user; that undertaking black-box Testing is the best way of ensuring that those parts of the applications that will be exposed to the user work correctly. Combined with the ease of use, quicker test case development and simplicity, black-box Testing represents a lower initial cost than white-box Testing and delivers ROI in a shorter period of time. Recognizing that to be the case, in the face of budgetary and time constraints, black-box Testing must be considered a necessary steps in quality assurance process.

Tools used for Black Box Testing

• • • VB script
    • Java Script
    • TSL
    • Perl

Summary

Black box testing focuses on the functionality of the system. We give input to the system and get the results to verify the functionality of the application. It do not involve in the inner code of the application. It can be performed even by the non-technical users. Therefore black box testing ensures that the system is working correctly according to the requirement of the user.

Conclusion

The customer uses the graphical interface of the system rather than the inner functionality of the system. Black box testing uses the graphical interface and checks the functionality of the system as a user objective. Although Black box testing do not cover the comprehensive testing of the system but it achieve the user’s goal for the functionality of the system. In conclusion we can say that the black box testing focus on the user objective and experience and the white box testing focuses on the internal working making sure that the system working correctly. So in user perspective it is good to use the black box testing for functional verification and delivering the bug free system to the user.

References:

1. Security testing-Wikipedia the free encyclopedia available

2. Software testing for Wikipedia available

3. Lessons Learned in Software Testing, by C. Kane, J. Bach, and B. Pettichord

4. Shilpa Testing Computer Software, by C. Kane, J. Falk, and H. Nguyen

5. Effective Software Testing, by E. Dustin